In a vacuum interrupter, a movable conductor is provided with a bellows, and airtightness of a vacuum vessel is maintained by expanding and contracting of the bellows with an operation of the movable conductor. The bellows is generally configured of metal such as stainless steel.
Atmospheric air or pressurized insulation gas is contained inside the bellows. On the other hand, vacuum is applied to the outer side of the bellows because its outside is inside the vacuum interrupter. Thus, because the inside pressure of the bellows is higher than the outside pressure of the bellows, and both ends of the bellows are restrained, buckling in which the bellows deforms may occur when a switch opening operation of the movable conductor is performed.
As a counter-measure for this problem, by increasing the outer diameter of the bellows, the buckling can be made difficult to occur.
As another counter-measure, for example, a vacuum interrupter can also be possible, in which a bellows is arranged outside a vacuum vessel as represented in Patent Document 1, and an end of the bellows is fixed to a movable end plate, while the other end is connected to a movable contact. According to this structure, because the inner side of the bellows is in a vacuum state, and the outer side of the bellows is in an atmospheric air or a pressurized insulation gas state, the buckling is difficult to occur.